Patent WO-2011010778-A1 (WO)
Title: Linear vibration motor
Inventor: KIM TAE JIN
IPC: H02K35/04
Filed: 2010-01-28
Abstract: The present invention relates to a linear vibration motor capable of vibrating electronic equipment. The linear vibration motor comprises: a casing that has a hollow interior and is open on one side; a bracket that is configured to close the open side of the casing and has an extension piece at the edge of one side thereof, the extension piece being projected outward of the casing; a magnet that is attached to the inner top surface of the casing and generates a magnetic field of a given direction and intensity; and a vibrator that is mounted inside the casing in such a manner as to face the magnet, the vibrator generating a magnetic field of a varying intensity and direction according to a specific frequency electrical signal transmitted from outside and then interacting with the magnetic field generated from the magnet to vibrate in a longitudinal direction of the casing. Also, the vibrator includes a connection piece that is inserted into the casing while facing the extension piece at one side thereof and can receive a specific frequency electric signal transmitted from outside; a moving piece that has an edge on one side connected to the connection piece to be able to receive the specific frequency electric signal transmitted from the connection piece and is movable in a longitudinal direction of the casing while being fixed to the connection piece; a coil that is mounted to one side of the moving piece on the opposite side of the magnet, the coil generating a magnetic field of a varying intensity and direction upon receiving an external electric signal transmitted to the moving piece via the connection piece and then interacting with the magnetic field of the magnet to move, together with the moving piece, in the longitudinal direction of the casing; and a weight that is mounted to an outer circumferential surface of the coil, thereby moving, together with the moving piece, in the longitudinal direction of the casing to maximize strength of the vibration. Further, a ring yoke is installed between the coil and the weight to uniformly deploy the magnetic field generated from the magnet and coil in a particular region such that the vibrating coil may not lean towards one direction inside the casing. Moreover, the vibrator has an elastic member interposed between the connection piece and the weight, both sides of the elastic member being coupled to one side of the bracket and one side of the weight, respectively, and a through hole is formed at the center of the elastic member to enable the moving piece to pass therethrough, thereby effectively transmitting the vibration that is generated from the weight coupled to the coil outside. The linear vibration motor having the above configuration according to the present invention can thus vibrate electronic equipment by employing a coil that generates a magnetic field of a varying intensity and direction according to a specific frequency electric signal transmitted from outside, a magnet that generates a magnetic field of a given intensity and direction all the time, and a weight and elastic member that can maximize the vibration of the coil moving vertically with respect to the magnet. Therefore, the linear vibration motor according to the present invention is advantageous in that the life of the vibration motor can be preserved semi-permanently by not using a brush and a rectifier that are applied to existing vibration motors.